Macular Photocoagulation Study (MPS)

The recruitment status of this study is unknown because the information has not been verified recently.
Verified June 2002 by National Eye Institute (NEI).
Recruitment status was  Active, not recruiting
Sponsor:
Information provided by:
National Eye Institute (NEI)
ClinicalTrials.gov Identifier:
NCT00000158
First received: September 23, 1999
Last updated: June 23, 2005
Last verified: June 2002

September 23, 1999
June 23, 2005
February 1979
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Complete list of historical versions of study NCT00000158 on ClinicalTrials.gov Archive Site
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Macular Photocoagulation Study (MPS)
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To evaluate laser treatment of choroidal neovascularization (CNV) through randomized, controlled clinical trials. The Macular Photocoagulation Study (MPS) consisted of three sets of randomized, controlled clinical trials. Change in best-corrected visual acuity from baseline was the primary outcome for all MPS trials. Other measures of vision are evaluated in each set of trials. The purpose of each is described below.

Argon Study: To determine whether argon blue-green laser photocoagulation of leaking abnormal blood vessels in choroidal neovascular membranes outside the fovea (200 to 2,500 microns from the center of the foveal avascular zone [FAZ]) is of benefit in preventing or delaying loss of central vision in patients with age-related (senile) macular degeneration (AMD), presumed ocular histoplasmosis (POH), and idiopathic neovascular membranes (INVM). A separate trial was conducted for each of the three underlying conditions.

Krypton Study: To determine whether krypton red laser photocoagulation of choroidal neovascular lesions with the posterior border 1 to 199 microns from the center of the FAZ is of benefit in preventing or delaying large losses of visual acuity in patients with AMD, POH, and INVM. A separate trial was conducted for each of the three underlying conditions.

Foveal Study: To determine whether laser photocoagulation is of benefit in preventing or delaying further visual acuity loss in patients with new (never treated) or recurrent (previously treated with laser photocoagulation) choroidal neovascularization under the center of the FAZ. Two separate trials, one for each type of lesion, were carried out.

In each randomized trial conducted by the MPS Group, focal laser photocoagulation was compared to observation without treatment. Patients were assigned to laser treatment or to observation with equal probability. The first set of MPS randomized trials, the Argon Study, focused on the effectiveness of photocoagulation with argon blue-green laser in eyes with discrete extrafoveal choroidal neovascularization. The study investigators, who began recruiting patients in 1979, estimated that 550 patients with AMD and 750 with POH would be required. Follow-up was to continue for 5 years to determine whether argon laser photocoagulation treatment could prevent or delay visual acuity loss in these patients.

After the initiation of the Argon Study, a new krypton red laser became available. The new wavelength offered theoretical advantages over the argon laser for treating CNV that extended inside the FAZ of the macula. The Krypton Study design was analogous to the Argon Study, with the investigation of three underlying conditions, except that CNV was closer to the FAZ center.

The third set of MPS clinical trials, the Foveal Study, was designed to determine whether laser photocoagulation was effective for delaying or preventing further visual acuity loss in AMD patients who have subfoveal CNV. Among patients assigned to laser treatment in the Foveal Study, argon laser treatment was compared with krypton red laser treatment of these lesions. The investigators originally projected that about 350 patients would be required for each clinical trial of the Foveal Study.

Interventional
Phase 3
Allocation: Randomized
Primary Purpose: Treatment
  • Choroidal Neovascularization
  • Macular Degeneration
  • Histoplasmosis
Procedure: Argon Blue-Green Laser Photocoagulation
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*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Active, not recruiting
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Common Eligibility Criteria for the Argon, Krypton, and Foveal Studies:

To be eligible, men and women must have been experiencing visual symptoms attributable to the macular lesion, such as decreased visual acuity or Amsler grid distortion, at the time of entry into the study. They also must have had visible, well-demarcated hyperfluorescence characteristic of classic choroidal neovascularization on fluorescein angiography. AMD patients were 50 years of age or older and had drusen visible in the macula of at least one eye. POH patients were at least 18 years old and had at least one characteristic histo spot in one or both eyes. INVM patients were at least 18 years old and had no evidence of AMD, POH, angioid streaks, high myopia, diabetic retinopathy, or any other condition that could be the cause of the neovascularization. In particular, INVM patients had neither drusen greater than MPS Standard Photograph No. 1.1 nor histo spots in either eye.

Additional Patient Eligibility Criteria for the Argon Study:

Each patient had a visible serous detachment of the sensory retina with a diffuse area of leakage, discrete choroidal neovascularization outside the fovea (200-2,500 microns from the center of the FAZ), and visual acuity of 20/100 or better in the study eye.

Additional Patient Eligibility Criteria for the Krypton Study:

All patients had a neovascular lesion consisting of neovascularization and possibly blood and/or pigment that extended into the FAZ. The posterior border of CNV could extend as close as 1 micron to the FAZ center. Visual acuity of the study eye was 20/400 or better.

Additional Patient Eligibility Criteria for the Foveal Study:

Only patients with AMD were eligible for this study. Fluorescein angiography of the eligible eye had to show evidence of a leaking choroidal neovascular membrane, some part of which extended under the center of the FAZ, or a neovascular lesion consisting of an old laser treatment scar and contiguous leaking neovascularization within 150 microns of the center of the FAZ. New, never-treated subfoveal lesions were less than four disc areas in size. Recurrent lesions were less than six disc areas in size, including the old treatment scar and new neovascularization. Best-corrected visual acuity was no better than 20/40 and no worse than 20/320.

Both
18 Years and older
No
Contact information is only displayed when the study is recruiting subjects
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NCT00000158
NEI-60
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National Eye Institute (NEI)
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National Eye Institute (NEI)
June 2002

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP